Citizenship of the Union - Right of residence of nationals of third countries who are family members of Union citizens - Refusal based on the citizen’s failure to exercise the right to freedom of movement - Possible difference in treatment compared with EU citizens who have exercised their right to freedom of movement - EEC-Turkey Association Agreement - Article 13 of Decision No 1/80 of the Association Council - Article 41 of the Additional Protocol - ‘Standstill’ clauses.